1. Field of the Invention
The present invention relates to a multi-chip bonding method and apparatus used in the manufacturing process of hybrid semiconductor devices.
2. Prior Art
In hybrid semiconductor devices, as shown in FIG. 2, semiconductor chips 2A and 2B of different types, e.g., two types, are mounted on a substrate 1. Prior art multi-chip bonding methods and apparatus for such mounting of semiconductor chips 2A and 2B of different types on a substrate 1 will be described below.
As shown in FIG. 3, the first method is a method in which wafer rings 4 (4A, 4B . . . ) or trays are exchanged for each individual substrate 1. The case of wafer rings will be described below.
As shown in FIG. 3, a wafer 3 pasted to the surface of a wafer sheet (not shown) is split longitudinally and laterally into a lattice form, and the wafer sheet is stretched so that individual semiconductor chips 2 (2A, 2B . . . ) are formed. The outer circumferential portion of the wafer sheet is attached to a wafer ring 4 (4A, 4B . . . ). The wafer rings 4 (4A, 4B . . . ) are accommodated in a wafer ring cassette 5 in which the rings are stacked in a vertical configuration with a fixed spacing maintained between the individual wafer rings, and this wafer ring cassette 5 is positioned and held in an elevator device (not shown). Here, wafer rings 4A, 4B . . . which have different types of semiconductor chips 2A, 2B . . . are accommodated in the wafer ring cassette 5. In other words, a wafer ring 4A which has semiconductor chips 2A, a wafer ring 4B which has semiconductor chips 2B, and so on, are accommodated.
A holding device 6 for holding wafer rings, trays, etc. (merely called xe2x80x9cholding device 6xe2x80x9d) is installed at a fixed distance from the wafer ring cassette 5 on the side of the accommodation opening of the wafer ring cassette 5. A push-up needle (not shown) which pushes the semiconductor chips 2 (2A, 2B . . . ) upward is installed beneath the pick-up position 7 of this holding device 6. The wafer rings 4 (4A, 4B . . . ) inside the wafer ring cassette 5 are chucked by a wafer ring conveying means (not shown) and are thus conveyed to the holding device 6, where the wafer rings are positioned and held. Furthermore, the wafer rings 4 (4A, 4B . . . ) that are held by the holding device 6 are chucked by wafer ring conveying means and accommodated in their original positions in the wafer ring cassette 5.
The above-described wafer ring cassette 5, elevator device (not shown) that positions and holds the wafer ring cassette 5, holding device 6, and wafer ring conveying means (not shown) are described in, for example, Japanese Patent Application Laid-Open (Kokai) Nos. H9-64147 and H9-64148. In Japanese Patent Application Laid-Open (Kokai) No. H9-64147, guide rails (wafer ring holder) for guiding wafer rings are vertically movable and horizontally rotatable near the wafer ring cassette, and the guide rails are set to be horizontal at the same height when the wafer is carried. In Japanese Patent Application Laid-Open (Kokai) No. H9-64148, a sensor for detecting wafer rings is provided on either the upper or lower claw provided in the wafer ring conveying means.
Meanwhile, the substrates 1 are accommodated in the substrate cassette 11 of a loader section 10. Each substrate 1 that is fed out from the substrate cassette 11 is conveyed by a substrate conveying device 12. An adhesive material is dropped onto the bonding portions of this substrate 1 by an adhesive material dropping device 20; then semiconductor chips (2A, 2B . . . ) are bonded to the bonding portions by a bonding apparatus 30, after which the substrate 1 is accommodate in the substrate cassette 14 of an unloader section 13.
The adhesive material dropping device 20 has a pre-forming nozzle 21 which accommodates the adhesive material; this pre-forming nozzle 21 is installed so that it is moved upward and downward on the Y table 23 of a universally known XY table 24 that consists of an X table 22 and Y table 23. The bonding apparatus 30 has a bonding tool 31 that holds the semiconductor chips 2 (2A, 2B . . . ) by vacuum suction and bonds the chips to the substrate 1. This bonding tool 31 is installed so that it is moved upward and downward on the Y table 33 of a universally known XY table 34 that consists of an X table 32 and Y table 33.
Next, the operation of the above apparatus will be described. In order to simplify the description, a case in which two types of semiconductor chips 2A and 2B are bonded to each substrate 1 as shown in FIG. 2 will be described.
The wafer ring 4A inside the wafer ring cassette 5 is conveyed by the wafer ring conveying means (not shown) and is positioned and held by the holding device 6. Then, the semiconductor chip 2A that is to be picked up is moved to the pick-up position 7.
Meanwhile, a substrate 1 inside the substrate cassette 11 of the loader section 10 is fed out onto the substrate conveying device 12. When this substrate 1 is conveyed to the adhesive material dropping station of the adhesive material dropping device 20 by the substrate conveying device 12 and positioned in this station, an adhesive material is dropped onto the bonding portions (located in six places in the case of FIG. 2) of the substrate 1 by the movement of the XY table 24 of the adhesive material dropping device 20 in the directions of the X and Y axes and the upward and downward movement of the preforming nozzle 21.
Next, when the substrate 1 onto which the adhesive material has been dropped is conveyed to the bonding station of the bonding apparatus 30 by the substrate conveying device 12 and is positioned in this bonding station, the bonding tool 31 of the bonding apparatus 30 vacuum-chucks a semiconductor chip 2A on the wafer ring 4A and is moved to point above the substrate 1, after which the bonding tool 31 bonds this semiconductor chip 2A to a bonding portion of the substrate 1 to which such a semiconductor chip 2A is to be bonded, in accordance with a method which will be described below.
The vacuum-chucking of the semiconductor chip 2A on the wafer ring 4A by the bonding tool 31, and the transfer and bonding of this chip to the substrate 1, are performed as follows: the bonding tool 31 is moved to a point above the pick-up position 7 by the XY table 34 and is then lowered, and the push-up needle (not shown) disposed beneath the pick-up position 7 is raised. As a result, the semiconductor chip 2A is pushed upward, and the bonding tool 31 chucks the semiconductor chip 2A by vacuum suction. The bonding tool 31 is then raised and is moved by the XY table 34 to a point above the bonding portion of the substrate 1 to which the semiconductor chip 2A is to be bonded. Next, the bonding tool 31 is lowered, and bonds the semiconductor chip 2A to the bonding portion of the substrate 1. Following this bonding, the vacuum of the bonding tool 31 is cut off, and the bonding tool 31 is raised. When the semiconductor chip 2A is picked up from the wafer ring 4A as described above, the next semiconductor chip 2A that is to be picked up is moved to the pick-up position 7.
Since four semiconductor chips 2A are bonded to each substrate 1 shown in FIG. 2, the operation in which the bonding tool 31 vacuum-chucks a semiconductor chip 2A from the wafer ring 4A and bonds this semiconductor chip 2A to a bonding portion of the substrate 1 is performed four times for each substrate 1.
When the bonding of the semiconductor chips 2A to the substrate 1 has been completed, the wafer ring 4A held by the holding device 6 is conveyed by the wafer ring conveying device (not shown) and accommodated in its original position in the wafer ring cassette 5. Next, the wafer ring cassette 5 is moved upward or downward by the elevator device (not shown), so that the wafer ring 4B is moved to the conveying level, and the wafer ring 4B inside the wafer ring cassette 5 is conveyed by the wafer ring conveying device and positioned and held by the holding device 6.
Then, by the method described above, the bonding tool 31 vacuum-chucks semiconductor chips 2B from the wafer ring 4B, and these semiconductor chips 2B are bonded to the bonding portions of the substrate 1 to which such semiconductor chips 2B are to be bonded. Since two semiconductor chips 2B are bonded to each substrate 1 shown in FIG. 2, the bonding of the semiconductor chips 2B is performed twice for each substrate 1.
When the bonding of the semiconductor chips 2A and 2B to a single substrate 1 has thus been completed, this substrate 1 is conveyed by the substrate conveying device 12 and accommodated inside the substrate cassette 14 of the unloader section 13. As a result of the above-described series of processes, the substrates 1 inside the substrate cassette 11 of the loader section 10 are successively conveyed by the substrate conveying device 12, the adhesive material is dropped onto the bonding portions by the adhesive material dropping device 20, and the semiconductor chips 2A and 2B are bonded to the bonding portions by the bonding apparatus 30. In this case, the wafer ring 4A is held by the holding device 6 as described above in order to bond the semiconductor chips 2A; then, when the semiconductor chips 2B are to be bonded, the wafer ring 4A is replaced by the wafer ring 4B, and this wafer ring 4B is held by the holding device 6.
As shown in FIG. 4, the second method is a method in which a plurality of wafer rings 4A through 4D or trays of different types are held by a holding device 40 for wafer rings, etc., and the desired wafer rings 4A through 4D or trays are selectively moved to the pick-up position 7. Here as well, the case of wafer rings 4A through 4D will be described.
As shown in FIG. 4, the holding device 40 for wafer rings, etc. is driven in the directions of the X and Y axes and supported so that it is free to rotate about a central shaft 41. Then, the holding device 40 is caused to rotate by a rotational driving means (not shown). Furthermore, in the example shown in FIG. 4, four wafer rings 4A through 4D of different types are positioned and held by the holding device 40 for wafer rings, etc. The remaining constructions, i.e., the loader section 10, substrate cassette 11, substrate conveying device 12, unloader section 13, substrate cassette 14, adhesive material dropping device 20 and bonding apparatus 30, are the same as in FIG. 3. Furthermore, a push-up needle (not shown) which pushes the semiconductor chips 2A through 2D upward is installed beneath the pick-up position 7 of the holding device 40 for wafer rings, etc.
Next, the operation of the above-described apparatus will be described. In the case of this method as well, a case in which two types of semiconductor chips 2A and 2B are bonded to each substrate 1 as shown in FIG. 2 will be described in order to simplify the description.
The method shown in FIG. 4 differs from the method shown in FIG. 3 only in the following respects:
In the method shown in FIG. 3, after all of the semiconductor chips 2A from the wafer ring 4A held by the holding device 6 have been bonded to the bonding portions for these semiconductor chips 2A on a single substrate 1, the wafer ring 4A held by the holding device 6 is replaced by the wafer ring 4B, and all of the semiconductor chips 2B are bonded to the bonding portions for these semiconductor chips 2B on the substrate 1. Then, the substrate 1 to which all of these semiconductor chips 2A and 2B have been bonded is accommodated in the substrate cassette 14 of the unloader section 13.
In the method shown in FIG. 4, the semiconductor chips 2A that are to be picked up from the wafer ring 4A are moved to the pick-up position 7 by rotating the holding device 40 for wafer rings, etc. Then, as in the case of FIG. 3, after all of the semiconductor chips 2A from the wafer ring 4A have been bonded to the bonding portions for these semiconductor chips 2A on a single substrate 1, the holding device 40 for wafer rings, etc. is rotated so that the semiconductor chips 2B that are to be picked up from the wafer ring 4B are moved to the pick-up position 7, and all of the semiconductor chips 2B from the wafer ring 4B are bonded to the bonding portions for these semiconductor chips 2B on the substrate 1 in the same manner as in FIG. 3. Afterward, the substrate 1 to which all of these semiconductor chips 2A and 2B have been bonded is accommodated in the substrate cassette 14 of the unloader section 13.
In the first method shown in FIG. 3, after all of the semiconductor chips 2A from the wafer ring 4A held by the holding device 6 have been bonded to the bonding portions (to which these semiconductor chips 2A are to be bonded) on a single substrate 1, the wafer ring 4A held by the holding device 6 is replaced by the wafer ring 4B, and all of the semiconductor chips 2B from the wafer ring 4B held by the holding device 6 are bonded to the bonding portions (to which these semiconductor chips 2B are to be bonded) on the substrate 1. More specifically, since it is necessary to exchange the wafer ring 4 (4A, 4B . . . ) for each substrate 1, the frequency with which the wafer ring 4 (4A, 4B . . . is exchanged is great, so that the productivity is poor.
In the second method shown in FIG. 4, a plurality of wafer rings 4A through 4D are held by the holding device 40 for wafer rings, etc., and the selection of the desired wafer ring 4A through 4D is accomplished merely by rotating the holding device 40 for wafer rings, etc.; accordingly, this method is superior in terms of productivity. However, the size of the holding device 40 for wafer rings, etc., is increased, and the apparatus is complicated. In the example shown in FIG. 4, four wafer rings 4A through 4D are held; however, in cases where five or more wafer rings are held, the size of the device is increased even further.
The object of the present invention is to provide a multi-chip bonding method and apparatus that causes no increase in the size of the holding device for wafer rings, etc., and improves the productivity.
The above objects are accomplished by a unique method and apparatus of the present invention, wherein
a substrate conveying device that conveys substrates,
first and second substrate supplying and accommodating sections that are respectively disposed at both ends of the substrate conveying device,
a bonding apparatus that bonds electronic components to the substrates conveyed by the substrate conveying device, and
a holding device which holds a wafer ring or tray that has electronic components, are provided; and
(i) a first wafer ring or tray which has electronic components of a first type that are to be bonded to the substrates is held by the holding device,
(ii) substrates are successively fed out to the substrate conveying device from the first substrate supplying and accommodating section,
(iii) the electronic components of the first type on the holding device are successively bonded to all of the bonding portions of the substrates to which electronic components of the first type are to be bonded,
(iv) the substrates on which the bonding of the electronic components of the first type has been completed are successively accommodated in the second substrate supplying and accommodating section,
(v) the first wafer ring or tray held by the holding device is exchanged by a wafer ring conveying device for a second wafer ring or tray which has electronic components of a second type that are to be bonded to the substrates, thus holding the second wafer ring or tray by the holding device,
(vi) the substrates accommodated in the second substrate supplying and accommodating section are successively fed out to the substrate conveying device,
(vii) the electronic components of the second type on the holding device are successively bonded to all of the bonding portions on the substrates to which electronic components of the second type are to be bonded, and
(viii) the substrates on which the bonding of the electronic components of the second type has been completed are successively accommodated in the first substrate supplying and accommodating section.
In the above, a dropping of an adhesive material on the bonding portions to which the electronic components of the first type are to be bonded on the substrates fed out of the first substrate supplying and accommodating section, and a dropping of an adhesive material on the bonding portions to which the electronic components of the second type are to be bonded on the substrates fed out of the second substrate supplying and accommodating section, are performed by a single adhesive material dropping device.
Alternately, the dropping of the adhesive material on the bonding portions to which the electronic components of the first type are to be bonded on the substrates fed out of the first substrate supplying and accommodating section, and the dropping of an adhesive material on the bonding portions to which the electronic components of the second type are to be bonded on the substrates fed out of the second substrate supplying and accommodating section, can be performed by respectively separate adhesive material dropping devices.